steam-frame/FEX-Emu--FEX
1
0 Fork 0
mirror of https://github.com/FEX-Emu/FEX.git synced 2026-10-23 12:00:46 +02:00
Code Issues Packages Projects Releases 67 Wiki Activity

OpcodeDispatcher: Implement SLDT

Browse Source 
Not 100% correct because the Linux kernel has some cheeky false data
return value when an LDT gets installed. But FEX can't really do it
properly today so whatever.
This commit is contained in:
Ryan Houdek committed 2026-10-22 15:29:16 -07:00
1 parent 4e2b509a42
commit 465395dede
5 files changed
+42 -6
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
+32 -1
View File
@@ -3156,7 +3156,38 @@ void OpDispatchBuilder::SMSWOp(OpcodeArgs) {
}
if (IsMemDst) {
// Memory destinatino always writes only 16-bits.
// Memory destination always writes only 16-bits.
DstSize = OpSize::i16Bit;
}
StoreResultGPR_WithOpSize(Op, Op->Dest, Const, DstSize);
}
void OpDispatchBuilder::SLDTOp(OpcodeArgs) {
const bool IsMemDst = DestIsMem(Op);
IR::OpSize DstSize {OpSize::iInvalid};
Ref Const = _Constant(0);
const auto OpAddr = X86Tables::DecodeFlags::GetOpAddr(Op->Flags, 0);
if (Is64BitMode) {
DstSize = OpAddr == X86Tables::DecodeFlags::FLAG_OPERAND_SIZE_LAST ? OpSize::i16Bit :
OpAddr == X86Tables::DecodeFlags::FLAG_WIDENING_SIZE_LAST ? OpSize::i64Bit :
OpSize::i32Bit;
if (!IsMemDst && DstSize == OpSize::i32Bit) {
// Special-case version of `sldt ebx`. This instruction does an insert in to the lower 32-bits on 64-bit hosts.
// Override and insert.
auto Dest = LoadSourceGPR_WithOpSize(Op, Op->Dest, GetGPROpSize(), Op->Flags);
Const = _Bfi(OpSize::i64Bit, 32, 0, Dest, Const);
DstSize = OpSize::i64Bit;
}
} else {
DstSize = OpAddr == X86Tables::DecodeFlags::FLAG_OPERAND_SIZE_LAST ? OpSize::i16Bit : OpSize::i32Bit;
}
if (IsMemDst) {
// Memory destination always writes only 16-bits.
DstSize = OpSize::i16Bit;
}
FEXCore/Source/Interface/Core/OpcodeDispatcher.h
+1
View File
@@ -488,6 +488,7 @@ public:
void SGDTOp(OpcodeArgs);
void SIDTOp(OpcodeArgs);
void SMSWOp(OpcodeArgs);
void SLDTOp(OpcodeArgs);
enum class VectorOpType {
MMX,
FEXCore/Source/Interface/Core/OpcodeDispatcher/SecondaryGroupTables.h
+5
View File
@@ -10,6 +10,11 @@ constexpr uint16_t PF_66 = 2;
constexpr uint16_t PF_F2 = 3;
constexpr DispatchTableEntry OpDispatch_SecondaryGroupTables[] = {
// GROUP 6
{OPD(FEXCore::X86Tables::TYPE_GROUP_6, PF_NONE, 0), 1, &OpDispatchBuilder::SLDTOp},
{OPD(FEXCore::X86Tables::TYPE_GROUP_6, PF_F3, 0), 1, &OpDispatchBuilder::SLDTOp},
{OPD(FEXCore::X86Tables::TYPE_GROUP_6, PF_66, 0), 1, &OpDispatchBuilder::SLDTOp},
{OPD(FEXCore::X86Tables::TYPE_GROUP_6, PF_F2, 0), 1, &OpDispatchBuilder::SLDTOp},
{OPD(FEXCore::X86Tables::TYPE_GROUP_6, PF_NONE, 3), 1, &OpDispatchBuilder::PermissionRestrictedOp},
{OPD(FEXCore::X86Tables::TYPE_GROUP_6, PF_F3, 3), 1, &OpDispatchBuilder::PermissionRestrictedOp},
{OPD(FEXCore::X86Tables::TYPE_GROUP_6, PF_66, 3), 1, &OpDispatchBuilder::PermissionRestrictedOp},
FEXCore/Source/Interface/Core/X86Tables/SecondaryGroupTables.cpp
+4 -4
View File
@@ -61,7 +61,7 @@ constexpr std::array<X86InstInfo, MAX_INST_SECOND_GROUP_TABLE_SIZE> SecondInstGr
// Pulls from other MODRM table
// GROUP 6
{OPD(TYPE_GROUP_6, PF_NONE, 0), 1, X86InstInfo{"SLDT", TYPE_UNDEC, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_NONE, 0), 1, X86InstInfo{"SLDT", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_NONE, 1), 1, X86InstInfo{"STR", TYPE_PRIV, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_NONE, 2), 1, X86InstInfo{"LLDT", TYPE_PRIV, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_NONE, 3), 1, X86InstInfo{"LTR", TYPE_INST, FLAGS_NONE, 0}},
@@ -70,7 +70,7 @@ constexpr std::array<X86InstInfo, MAX_INST_SECOND_GROUP_TABLE_SIZE> SecondInstGr
{OPD(TYPE_GROUP_6, PF_NONE, 6), 1, X86InstInfo{"", TYPE_INVALID, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_NONE, 7), 1, X86InstInfo{"", TYPE_INVALID, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_F3, 0), 1, X86InstInfo{"SLDT", TYPE_UNDEC, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_F3, 0), 1, X86InstInfo{"SLDT", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_F3, 1), 1, X86InstInfo{"STR", TYPE_PRIV, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_F3, 2), 1, X86InstInfo{"LLDT", TYPE_PRIV, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_F3, 3), 1, X86InstInfo{"LTR", TYPE_INST, FLAGS_NONE, 0}},
@@ -79,7 +79,7 @@ constexpr std::array<X86InstInfo, MAX_INST_SECOND_GROUP_TABLE_SIZE> SecondInstGr
{OPD(TYPE_GROUP_6, PF_F3, 6), 1, X86InstInfo{"", TYPE_INVALID, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_F3, 7), 1, X86InstInfo{"", TYPE_INVALID, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_66, 0), 1, X86InstInfo{"SLDT", TYPE_UNDEC, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_66, 0), 1, X86InstInfo{"SLDT", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_66, 1), 1, X86InstInfo{"STR", TYPE_PRIV, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_66, 2), 1, X86InstInfo{"LLDT", TYPE_PRIV, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_66, 3), 1, X86InstInfo{"LTR", TYPE_INST, FLAGS_NONE, 0}},
@@ -88,7 +88,7 @@ constexpr std::array<X86InstInfo, MAX_INST_SECOND_GROUP_TABLE_SIZE> SecondInstGr
{OPD(TYPE_GROUP_6, PF_66, 6), 1, X86InstInfo{"", TYPE_INVALID, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_66, 7), 1, X86InstInfo{"", TYPE_INVALID, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_F2, 0), 1, X86InstInfo{"SLDT", TYPE_UNDEC, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_F2, 0), 1, X86InstInfo{"SLDT", TYPE_INST, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_F2, 1), 1, X86InstInfo{"STR", TYPE_PRIV, FLAGS_MODRM | FLAGS_SF_MOD_DST, 0}},
{OPD(TYPE_GROUP_6, PF_F2, 2), 1, X86InstInfo{"LLDT", TYPE_PRIV, FLAGS_NONE, 0}},
{OPD(TYPE_GROUP_6, PF_F2, 3), 1, X86InstInfo{"LTR", TYPE_INST, FLAGS_NONE, 0}},
FEXCore/include/FEXCore/Core/CoreState.h
-1
View File
@@ -247,7 +247,6 @@ struct alignas(64) CPUState {
// Follows encoding of the TI bit in segment selector encoding.
constexpr static uint32_t SEGMENT_ARRAY_INDEX_GDT = 0;
constexpr static uint32_t SEGMENT_ARRAY_INDEX_LDT = 1;
Core::CPUState::gdt_segment private_gdt[32] {};
};
static_assert(std::is_trivially_copyable_v<CPUState>, "Needs to be trivial");
static_assert(std::is_standard_layout_v<CPUState>, "This needs to be standard layout");